The present invention relates to elastomeric gaskets and, more specifically, gaskets for providing a fluid tight seal between a pair of tubular members, particularly corrugated pipe.
It is well known to form a seal between two pipe sections where the end of one of the pipe sections has annular grooves and one of the pipe sections has an enlarged bell portion. An elastomeric gasket is placed around the end of the pipe section having annular grooves. The pipe section having annular grooves is inserted into an enlarged bell portion of a second pipe section.
Prior art gaskets are adapted to fit in the groove of a corrugated pipe. As one end of a pipe is pushed into the enlarged end of another pipe section, the gasket is sometimes pulled from the groove and the pipe is not properly sealed. When the pipe is not properly sealed ground water may leak into the pipe or fluid may leak out of the pipe and contaminate the ground.
U.S. Pat. No. 4,702,502 attempted to solve the problem where the gasket was pulled from the annular grooves of a corrugated pipe when the corrugated pipe was inserted into a bell portion of a second corrugated pipe. The ""502 patent concerned a telescopic joint in low pressure corrugated plastic pipe. The joint includes a one piece elastomeric gasket that has a sealing portion adapted to be disposed in a groove in one of the pipes and an anchoring portion adapted to be disposed in an adjacent groove. As the pipes are telescoped together the anchoring portion is trapped in the groove and anchors the sealing portion in place as it is compressed.
Typically, the grooves of a corrugated pipe do not have a very tight tolerance. If a gasket rolls as the first and second pipe sections are assembled, a fluid tight seal may not result or the corrugated pipe could be damaged. A gasket is needed that can accommodate a corrugated pipe having grooves of a variety of sizes, does not roll as one pipe section is inserted into a second pipe section, and provides a wedging action to assure a tight seal under pressure.
The present invention relates to an improved compressible annular gasket for providing a fluid-tight seal between a first tubular member and a second tubular member. The first tubular member, such as a corrugated pipe, typically has a plurality of annular grooves and ridges. The second tubular member typically has a smooth annular section. The gasket of the present invention seals the two tubular members when an end of the first member is inserted into the smooth annular section of the second member. The compressible annular gasket comprises an anchor portion and an elongated portion. The anchor portion is sized to fit in one of the grooves of the corrugated pipe. In one embodiment, the anchor portion has a rounded external surface that is accommodated in a groove of the corrugated pipe, and one or more circumferential ridges extend from the anchor portion, serving to hold the bulbous portion in the groove of the corrugated pipe. The elongated portion extends axially of the tubular member from the anchor portion in a direction generally opposite from the ridge or ridges. When the anchor portion is installed in one of the grooves of the corrugated pipe, the elongated portion extends in a direction away from the open end of the pipe to which it is affixed and at least partially across an annular ridge of the corrugated pipe adjacent to the groove that receives the anchor portion. The elongated portion of the gasket makes sealing contact with the smooth annular section of the second pipe when the first tubular member and the smooth annular section of the second member are in a relative surrounded and surrounding relationship. The elongated portion is tapered, allowing the gasket to be pulled into increasingly tight engagement with the first and second tubular members as the smooth annular section is relatively moved onto the end of the first pipe and over the gasket.
In a broad aspect, the invention provides a compressible annular gasket for providing a fluid-tight seal between a first tubular member having an annular groove and a smooth annular section of a second member when the first tubular member and the smooth annular section are in a relative surrounded and surrounding relationship. The gasket includes an anchor portion adapted to be disposed in a groove and an elongated portion adapted to extend across an annular ridge when the anchor portion is disposed in a groove. The anchor portion includes an external surface sized to both fit in a groove and inhibit removal of the anchor portion from the groove. The elongated portion is adapted to extend axially from the anchor portion and make contact with an annular section when the tubular member having a groove in which the gasket is received and a smooth annular section are in relative surrounded and surrounding relationship.
Additional features of the invention will become apparent and a fuller understanding obtained from the following detailed description in connection with the accompanying drawings.